You know how smartphones have a battery accessory? Well, there is a lot of electrical cars that could use a little back-up battery. What you are seeing on the back of this car is an EP Tender, and it is a generator on wheels. It is connected to the car's battery via a cable, and the generator switches on and feed the battery its necessary juice. It is capable of 22kW … [Read more...] about EP Trailer is a backup charger for an electrical vehicle